Browsing by Author "Rani, Pinki"

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    Enhancing the electrochemical performance of TiO2 based material using microwave air plasma treatment with an ECR cavity
    (Frontiers Media S.A., 2022-11-24T00:00:00) Swaroop, Ram; Rani, Pinki; Jamwal, Gaurav; Sabavath, Gopikishan; Kumar, Haldhar; Jewariya, Yogesh
    The microwave-based plasma treatment facility at the Central University of Punjab Bathinda (CUPB) based on 2.45�GHz has been used to investigate the impact on the electrochemical performance of TiO2. This was accomplished by treating a number of pellets of TiO2 sample material with microwave plasma at an input power of 80�W. The palette is subjected to microwave plasma treatment at 30-, 60-, 80-, and 100-s intervals. Many such characterization methods, including UV-visible spectroscopy, FTIR, XRD, and FESEM, have been applied to the study of the impact of plasma treatment on other physical and chemical properties in the context of untreated pellets. In the 80-s plasma treatment, the FTIR study showed that the (O-Ti-O) vibration band at 500�900�cm?1 was wider than other bands. The UV results showed that an 80-s plasma treatment decreased the sample�s band gap by 37% and increased the amount of disordered, amorphous material in the sample that had not been treated. XRD studies show that a sample that was treated with plasma for 80�s has low crystallinity and a high disorder (amorphous) factor. The Nyquist plot showed that the electrochemical charge transfer resistance drops from 7 (not treated) to 4 after 80�s of plasma treatment. In a study of electrochemical performance, a sample that was treated with plasma for 80�s has a capacitance that is 35% higher than a sample that was not treated. Copyright � 2022 Swaroop, Rani, Jamwal, Sabavath, Kumar and Jewariya.
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    Preparation and Energy Storage Assessment of Ti3C2 2d MXene and Its Possible Thinning Mechanism
    (Springer Nature, 2023-09-07T00:00:00) Singh, Diya; Rani, Pinki; Biswas, Sayani; Alegaonkar, Prashant S.
    Since after its discovery, MXene has captivated the focus of many researchers. In this work, we report on the low-temperature synthesis of Ti3AlC2 MAX phase at 800�? and its further etching to obtain Ti3C2 MXene. Initially, titanium (Ti), aluminium (Al), and graphite (C) precursors were taken in an appropriate volume proportion and add-mixed and grounded well via molten salt technique (Galvin et al. in J Eur Ceram Soc 38, 2018 [1]). The characterizations performed on powder such as FTIR, XRD, UV�Visible, SEM, and EDS confirmed Ti3AlC2 MAX phase. The MAX phase was subjected to the acid treatment (HF, concentration 40%) for ~ 80�h. The synthesized MXene was separated and investigated using FTIR, XRD, UV�Visible, SEM, and EDS techniques. The MXene was further employed to microwave treatment over the temperature 300�420�K at a discharge of power 120 W for 1�h. Analysis revealed that thickness of Ti3C2 layers is observed to be decreased with microwave treatment which can be a possible mechanism to obtain MXene quantum dots. In electrochemical analysis, specific capacitance for two electrode MXene@300�K and @400�K is reported to be 15 and 10�F/g, respectively, showing resistive nature of capacitance coupling for MXene. Analysis of electrochemical impedance spectroscopy together with bode showed the surface passivation effect of MXene layers to achieve different charge dynamics in both the systems. � 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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    Reduced graphene oxide doped tellurium nanotubes for high performance supercapacitor
    (Frontiers Media S.A., 2022-10-20T00:00:00) Rani, Pinki; Alegaonkar, Ashwini P.; Biswas, Rathindranath; Jewariya, Yogesh; Kanta Haldar, Krishna; Alegaonkar, Prashant S.
    Supercapacitors have been achieving great interest in energy storage systems for the past couple of decades. Such devices with superior performance, mainly, depending on the material architecture of the electrodes. We report on the preparation of Tellurium nanotubes (Te-tubes diameter ?100�nm and length ?700�nm), with variable doping of conducting network reduced graphene oxide (rGO) to fabricate high-performance electrode characteristics of rGO @ Te. The prepared material was characterized using XRD, FTIR, FESEM, and Raman spectroscopy techniques, including Brunauer-Emmett-Teller, Barrett-Joyner-Halenda measurements. FTIR study revealed that 15% rGO @ Te has a wide C-O vibration band at ? 1,100�1,300�cm?1, over other compositions. FESEM study shows the Te-tubes dispersion in rGO layers. The EDX study revealed that 15% of the composition has an optimistic concentration of C and O elements. In other compositions, either at lower/higher rGO concentration, an uneven count of C and O is observed. These support efficient charge dynamics to achieve superior ultra-capacitor characteristics, thereby achieving specific capacitance Csp 170 + F/g @ 10�mV/s in a symmetric configuration. The reported values are thirty times higher than pristine Te-tubes (?5�F/g). This finding suggests that rGO @ Te is a promising candidate for supercapacitor. Copyright � 2022 Rani, Alegaonkar, Biswas, Jewariya, Kanta Haldar and Alegaonkar.
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    Synergistic photophysical and electrochemical response of Te @ PANI for energy harvesting
    (Springer, 2023-01-07T00:00:00) Rani, Pinki; Jewariya, Yogesh; Haldar, Krishna Kanta; Biswas, Rathindranath; Alegaonkar, Prashant S.
    Materials with synergistic functionality are of great importance in consumer electronics. We report on the preparation and assessments of Te @ PANI composite for energy conversion and storage application. Initially, (5�15%) Te @ PANI composites were synthesized by the facile, room temperature, time and cost-effective solid-state synthesis technique followed by characterizations using Fourier transform infra-red, UV-Visible, energy dispersive spectroscopic including X-ray diffractometry and field electron scanning microscopy. Te exfoliates polymeric segments of PANI by bonding benzenoid rings through sulphonated impurity sites which have a profound impact on symmetry molecular bond vibrations. Its analysis is presented. In photophysical application, both dark and luminescent I-V measurements have been performed that showed a linear variation with minimum photo-resistance offered by 10% composite and reaching current > 10�mA under 1.5�V biased conditions. In storage response, Te @ PANI supercapacitor devices are dominating in inductive coupling over capacitive coupling by ten times. Corresponding shunt impedance is seen to be favourably lower for 10% composition, and respective charge transfer impedance has also followed identical behaviour over other classes of samples. The quality factor of the device for 10% is found to be almost twelve times better. However, at a low scan rate (10�mV/s), the presence of Te has changed the tendency of ion migration, thereby, reducing the magnitude of ion current by about three times with an increase in Te from 5 to 15%. Thus, fabricated composite demonstrated synergistic aspects of energy. � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
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    Tellurium nanostructures for optoelectronic applications
    (Springer Science and Business Media Deutschland GmbH, 2022-03-29T00:00:00) Rani, Pinki; Alegaonkar, Ashwini P.; Mahapatra, Santosh K.; Alegaonkar, Prashant S.
    We report on fabrication of tellurium nanostructures (TN) that demonstrated promising applications in optoelectronics. Initially, TN were synthesized using a simple, one-step, room temperature, wet-chemical technique. During synthesis, the effect of number of parameters such as precursor concentration, its content, solvent ratios, their pH and reaction time has been investigated at a temperature ~ 120��C. The obtained product was examined by UV�visible, IR spectroscopy, X-ray diffractometry, electron microscopy and energy-dispersive X-ray spectroscopic characterization techniques. Analysis revealed that TN have profound impact on the structure�property relationship through active and passive participation of Mo catalyst. During its initial growth stages, Te and O bonding gets influenced by Mo to form Mo�O�Te�O and Te�Mo�Te moieties, typically, at 6�h. This has implication onto the structural phase transformation of TN from Te-tube (TT) to Te-flake (TF) and then to TT again. Possible transformation mechanism is explained. Structurally, TN had hexagonal quasi-crystalline atomic arrangement with morphologically thin, transparent, bunched and close-caped TT characteristics having diameter 50�100�nm and length 0.8�2.1��m, whereas TF is found to be thin, geometrically squared with area ~ 7 to 10 �m2. On their implementation for optoelectronic assessments, over the wavelength range 0.3�2.1��m (power density ~ 100 mW/cm2), they showed peculiar luminescent and dark I�V responses. Relevant photocarrier dynamics has been revealed. TT, typically, showed 160% quantum efficiency, whereas TF ~ 40% is useful for optoelectronic devices. Details are presented. Graphical abstract: Fabrication and optoelectronic assessments of tellurium nanostructure that showed time-dependent structural phase transformation from tube to flake to tube. [Figure not available: see fulltext.] � 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
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    Thermophysical Assessments on Self-Assembled Tellurium Nanostructures
    (American Chemical Society, 2023-09-01T00:00:00) Sudheer, Manjima; Rani, Pinki; Patole, Shashikant P.; Alegaonkar, Prashant S.
    Thermal properties of self-assembled nanostructures are of great importance to explain the structural phase transformation phenomenon. We report on the thermophysical assessments on tellurium nanostructures (TeN) that have been prepared using a facile wet-chemical technique by admixing precursor sodium telluride (Na2TeO3) and sodium molybdate (Na2MoO4) catalysts in hydrazine hydrate solution and heated at 120 �C, over 5-7 h. The extracted products (interval: 0.5 h) were subjected to a number of spectro-microscopic techniques including thermal measurements. Under identical growth conditions, the morphology of TeN was found to be transformed from Te nanotube (TT) to Te nanoflake (TF) at 6 h. Analysis revealed that Mo participated actively during 6 h of growth time, thereby making bonds with oxygen and the Te host lattice. At the vicinity of the phase transformation, Mo acquired an interstitial position in the hexagonal motif due to enhancement in catalytic efficiency that led to the formation of MoO2- moieties, which transiently reacted with host lattices resulting in surface charging of the tubes. This, in turn, created the coalescing effect with neighboring colloidal tubes through the van der Waals interaction. Thermal properties such as thermal conductivity, effusivity, diffusivity, and specific heat studied for TeN showed prominent surface effects. The increased surface area and enhanced amount of polycrystallinity resulted in unprecedently low thermal properties of TF due to severe phonon confinement. � 2023 American Chemical Society.